As the charged particle circulation system, a synchrotron or the like is known. As the synchrotron, there is the small-size synchrotron which is reduced in size to a diameter of approximately 60 cm, for example. The small-size synchrotron comprises a perturbation device for a charged particle circulation system, which captures the charged particles injected into the charged particle circulation system into a stable circular closed orbit. The perturbation device partially superposes a perturbation magnetic field on a main magnetic field for circulating charged particles so that perturbation is produced in the trajectories of the charged particles. The perturbation device is referred to as a “perturbator”.
The charged particle circulation system such as the synchrotron further comprises a high-frequency acceleration cavity arranged on the stable circular closed orbit. The high-frequency acceleration cavity accelerates the charged particles that circulate in the stable circular closed orbit, after the perturbation device such as the perturbator has produced perturbation in the stable circular orbit and captured the charged particles injected into the charged particle circulation system into the stable circular orbit.
In the paper entitled “Novel X-ray Generated by Tabletop Synchrotron “MIRRORCLE-20” (Nonpatent Document 1), presented by Hironari Yamada in “Journal of the Japanese Society for Synchrotron Radiation Research”, Vol. 15, No. 3, pp. 15-27, and in the paper entitled “Injection System of Compact SR Light Source “AURORA” Single Body Superconducting Ring” (Nonpatent Document 2), presented by Takeshi Takayama et al. in “Sumitomo Heavy Industries Technical Review”, Vol. 1.39, No. 116, August 1991 pp. 11-18, for example, a perturbation device is described. The perturbation devices described in these papers, partially superpose a perturbation magnetic field on a main magnetic field for circulating charged particles in a synchrotron, so that perturbation is produced in the trajectory of the charged particles and the charged particles injected into the synchrotron are captured into a stable circular orbit.
A relationship between the synchrotron and the perturbation device will be described, using FIGS. 9 and 10. FIG. 9 simulatively illustrates that the perturbation device and a high-frequency acceleration cavity are arranged on the stable circular closed orbit of the synchrotron. FIG. 10 simulatively illustrates that injected charged particles are circulating in the stable circular closed orbit.
FIG. 9 simulatively illustrates that a perturbation device 1 which is constituted by the perturbator and a high-frequency acceleration cavity 3 are arranged on a stable circular closed orbit 5 of the synchrotron. FIG. 9 also shows the trajectories of the charged particles that have been perturbated by the perturbator while being injected into the synchrotron. FIG. 10 simulatively illustrates that the injected charged particles or an accumulating electron beam in the form of electron bunches (group of electrons) are circulating on the stable circular closed orbit 5. In these figures, reference numeral 7 denotes a central orbit that is present in the center of the stable circular closed orbit 5. Incidentally, in FIGS. 9 and 10, a main magnet that forms the orbit of circulating electrons and prevents diverge of the electron beam is omitted from the illustration.
This synchrotron uses a resonance injection method in which an injection trajectory is produced without influencing the accumulating electron beam. When an electron beam is injected using the resonance injection method, electrons are in a resonance state at the time of the injection, and betatron oscillation amplitudes of the electrons have become large. If a high-frequency acceleration voltage is applied to the high-frequency acceleration cavity 3 when the betatron oscillation amplitudes of the electrons are large, the electrons will scatter and jump out of the stable circular closed orbit 5.
Then, the electrons (charged particles) by the high-frequency acceleration cavity 3 is not actively accelerated until betatron oscillation of the electrons (charged particles) is reduced and the electrons (charged particles) circulate on the stable circular closed orbit 5, after perturbation has been produced in the stable circular closed orbit 5 by the perturbation device 1 and the electrons (charged particles) have been captured into the stable circular closed orbit 5.
The size of the electron bunch (group of electrons) is smaller when energies of the electrons are high. When the energies of the electrons are low, the size of the electron bunch increases. In recent years, the synchrotron has come to be used when the energies of the electrons are low. Non-patent Document 1: Paper Entitled “Novel X-ray Generated by Tabletop Synchrotron “MIRRORCLE-20”, presented by Hironari Yamada in “Journal of the Japanese Society for Synchrotron Radiation Research”, vol. 15, No. 3, pp. 15-27.
Non-patent Document 2: Paper Entitled “Injection System of Compact SR Light Source “AURORA” Single Body Superconducting Ring”, presented by Takeshi Takayama et al. in “Sumitomo Heavy Industries Technical Review”, Vol. 1.39, No. 116, August 1991 pp. 11-18.